What mass, in grams, of sodium chloride is needed to prepare 15.0 ml of 10% (m/v) NaCl solution?
To determine the mass of sodium chloride (NaCl) needed to prepare the given solution, we need to follow these steps:
Step 1: Understand the information given in the question.
- The volume of the solution is 15.0 mL.
- The concentration of the solution is 10% (m/v), which means 10 grams of NaCl is present in 100 mL of the solution.
Step 2: Calculate the mass of NaCl needed for 100 mL of the solution.
- Since the concentration is 10% (m/v), 10 grams of NaCl is present in every 100 mL of the solution. Therefore, the mass/volume ratio is 10 grams / 100 mL.
Step 3: Apply the mass/volume ratio to calculate the mass of NaCl needed for 15.0 mL of the solution.
- We can set up a proportion to solve for the unknown mass of NaCl:
(10 grams / 100 mL) = (x grams / 15 mL).
- Cross-multiplying the proportions, we get:
100x = 10 * 15.
- Simplifying the equation, we find:
100x = 150.
- Now, divide both sides of the equation by 100:
x = 150 / 100.
- Therefore, the mass of NaCl needed for 15.0 mL of the solution is:
x = 1.5 grams.
Therefore, you would need 1.5 grams of sodium chloride to prepare 15.0 mL of a 10% (m/v) NaCl solution.